Brake assembly for wheelchairs



I Sept. 22, 1910 H. E. MARSHALL 3,529,700

BRAKE ASSEMBLY FOR WHEELCHARS 'Filed oor. 28, 196s 5 Sheets-She@ l Sept 22, 1970 H. E. MARSHALL 3,529,700

BRAKE ASSEMBLY FOR WHEELCHARS Filed Oct. 28, 1968 .3 Sheets-Sheet 2 Mfr ,MW

Sept. 22, 1970 H.. E. MARSHALL BRAKE ASSEMBLY FOR WHEELCHAIRS Filed 001;.

.'5 Sheets-Sheet 5 FIG.7

United States Patent O 3,529,700 BRAKE ASSEMBLY FOR WHEELCHAIRS Harold E. Marshall, 2600 Spies Drive, Arnold, Mo. 63010 Filed Oct. 28, 1968, Ser. No. 770,975 Int. Cl. B60t 1/04, 13/04; F16d 65/30 U.S. Cl. 18S-109 13 Claims ABSTRACT OF THE DISCLOSURE A wheelchair brake assembly including spring loaded brake elements mounted on the main frame of a wheelchair and biased toward wheel engagement. The elements are disengaged from the wheels in response to a seat controlled linkage or manually operable means.

BACKGROUND OF 'I'HE INVENTION I This invention relates to a wheelchair having automatic auxiliary wheel locking devices.

Many invalids confined to wheelchairs are capable of leaving their wheelchairs for sho-rt distances when some object such as a handrail is available for them to grasp. However, it is important that the wheelchair be locked or stabilized so that it will remain in the same place and does not move as the invalid sits down or stands up. A serious hazard exists for the invalid who fails to set the conventional hand 4brakes prior to leaving the chair, particularly for invalids who are mentally deficient or senile.

Semi-invalids capable of limited mobility or during recuperation utilize various separate devices for therapy, such as fixed bars and conventional walkers. Although some such invalids may use their wheelchairs as walkers, this practice has not been recommended inasmuch as the conventional hand brakes are not conveniently accessible to one standing upright behind the chair and, if the invalid loses his balance, there is no way to stabilize the wheelchair or prevent its rolling away from him.

SUMMARY OF THE INVENTION The present invention is embodied in a brake assembly having spring loaded Ibraking means normally biased into engagement with the rear wheels and 'being connected for movement to a disengaged position in response to the weight of an individual on the seat of the chair. The braking means can also be released from the wheels by manipulating manually operable means at the rear of the chair so that the chair can be moved without someone sitting upon it.

One `of the principal objects of the present invention is to provide a wheelchair brake assembly which automatically locks the wheels when the invalid leaves the wheelchair. Another object is to provide a wheelchair brake that can be manually manipulated from the rear of the chair so that an invalid capable of limited mobility can safely utilize the chair as a walker. Still another object is to. provide a wheelchair brake kit for converting conventional wheelchairs to incorporate the present invention. A further object is to provide a wheelchair brake assembly that is rugged in construction, simple to Operate, and economical to manufacture.

. These and other objects and advantages will become apparent hereinafter.

yBRIEF DESCRIPTION OF THE DRAWINGS The invention is also embodied in the parts and in the arrangements and combinations of parts hereinafter described and claimed. In the accompanying drawings which form a part of this specification and wherein like numerals refer to like parts wherever they occur:

Patented Sept. 22, 197() ICC FIG. 1 is a perspective view of a wheelchair having a brake assembly embodying the present invention;

FIG. 2 is a diagrammatic view (from the rear of a wheelchair) of the brake assembly;

FIG. 3 is a bottom plan view of the wheelchair;

FIG. 4 is a side elevational View, partially broken away and in section, of a wheelchair having a modified brake assembly embodying the present invention;

FIG. 5 is a rear elevational view of the modified brake assembly illustrated in FIG. 4;

FIG. 6 is a fragmentary sectional view of the modified brake assembly, taken along line `6 6 of FIG. 4;

FIG. 7 is a fragmentary rear elevational view showing another modification of the brake assembly;

FIG. 8 is an enlarged cross-sectional view of the modification taken substantially along line 8-8 of FIG. 7; and

FIG. 9 is an enlarged cross-sectional view of the modi fication taken substantially along line 9-9 of FIG. 7.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now in detail to the drawings, the present invention as illustrated is applied to a wheelchair 2 of the type that can be folded or collapsed to fit more conveniently into confined spaces (as shown in broken lines in FIG. 5), 'but it will be readily apparent that the invention is also applicable to non-folding wheelchairs of the institutional variety.

The wheelchair 2 includes a main frame 4 having a pair of rigid side frames 6 and a seat unit 5 interconnected by front and rear sets of cross members 8 and 10, respectively. Each side frame 6 is preferably of tubular construction and includes an upstanding rear member 12 formed with a short horizontal portion at its upper end to provide a hand grip or support 14, a lower horizontal member 16 provided with a foldable foot rest 18, an upstanding front member 20 welded to the lower member 16, and an upper horizontal member 22 formed integral with the front member 20 and being welded at its rear end to the side of the upstanding rear member 12 so that the end face 23 of the horizontal member 22 is exposed and presented rearwardly. An arm rest 24 is secured on the upper member 22, and a side panel 25 may be provided between the rear and front members 12 and 20. Each upstanding rear member 12 is fitted with a laterally projecting spindle 26 on which is journaled a rear propulsion wheel 28 having a rubber tire 30. The tire 30 is engageable by a conventional hand brake assembly (not Shown) conveniently located on the side frames 6 for operation by a patient sitting in the chair 2. Each lower horizontal member 16, immediately rearwardly from its corresponding front member 20, mounts a castertype foot wheel assembly 32.

The rear cross members 10 are pinned to the upstanding rear members 12 adjacent to the lower horizontal members 16, while the front cross members 8 are pivotally connected to upwardly projecting tabs attached to the lower horizontal members 16. The front and rear sets of cross members 8 and 10 are pivoted for scissors action between the open and collapsed positions shown in FIG. 5 and the upper ends of the front and rear cross members 8 and 10 are secured to longitudinally extending seat bars 34 of the seat unit 5 which also has a flexible seat panel 36 attached to the bars 34. A flexible back panel 38 is attached to the upstanding rear members 12. The rear cross members 10 are further joined to the upstanding rear members 12 through a pair of stabilizing links 39.

When wheelchair 2 is in its open or erected position, as illustrated in FIG. l and in solid lines in FIG. 5, the side frames 6 are spaced fully apart by the iront and rear cross members 8 and 10 with the stabilizing links 39 in a substantially horizontal position and the seat bars 34 positioned adjacent to the lower margin of the back panel 39. The seat panel 36 and the back panel 39 are stretched taut between the seat supports 34 and upstanding rear members l2, respectively. The wheelchair 2 is collapsed to the broken line position shown in FIG. 5 by merely lifting or moving the seat bars 34 toward each other, thereby raising the bars 34 to a level adjacent to the upper members 22 and drawing the side frames 6 together.

The wheelchair 2 is provided with a brake assembly 40 embodying the invention and comprising a pair of brake arms 42 pivotally mounted on the main frame 4 and having braking margins 41 normally biased into braking engagement with the tires 30. In the construction of the wheelchair 2 selected for disclosure, the exposed tubular ends 23 of the upper side frame members 22 is positioned above the tire 30 and provides a convenient means for pivotally mounting the brake arms, but it will be apparent that in other typical wheelchair constructions, brackets (not shown) may be used to pivotally secure the braking means 42 on the main frame 4 for engagement with the tires 30. In the preferred arrangement, the brake arms 42 are journaled on pins 43 set into plugs 44, which are press fitted or otherwise secured in the exposed tubular ends 23 of the upper horizontal members 22. Each brake arm 42 projects laterally beyond the side frame 6 so that the lower edge or margin 41 extends laterally across the tire 30 of the main drive wheel 28. The brake arms 42 pivot in a transverse plane relative to the plane of rotation of the wheels 28 between a disengaged position wherein their lower edges 41 are located slightly above the tires 30 and an engaged position in which the lower margins 41 engage the rubber tires 30 and prevent rotation of the rear wheels 28.

Referring to the embodiment shown in FIGS. l-3, the brake arms 42 are biased toward their engaged positions by coiled tension springs 45 which extend between the inner control ends 41' of the arms 42 and the upper ends of the upstanding rear members 12.

Beneath the seat panel 36, a pair of transversely extending webs 46 are suspended between the seat bars 34, and these webs 46 are in turn interconnected intermediate their ends by a pair of closely spaced longitudinal connecting webs 48 to form a webbed harness beneath the seat panel 36 (FIG. 3). The webs 46 and 48 are fastened to and carry a pair of rigid actuating bars or lever members 5t) which extend longitudinally along the webs 48 and project rearwardly beyond the rear edge of the seat panel 36 where they are connected to the ends of the brake arms 42 by means of flexible, non-stretchable connecting chains or cables 52. The lengths of the cables 52 are such that when the brake arms 42 are in their engaged positions, the actuating members 50 will be elevated slightly and will lift both the webs 46 and seat panel 30` slightly above the position they would otherwise assume if they were suspended freely between the seat supports 34. Therefore, when a person is seated in the wheelchair 2, the seat panel 30 is depressed and the cables 52 and inner ends 41 of the brake arms 42 will be drawn downwardly against the bias of the springs 45, thus rotating the arms 42 and moving the braking margins 41 upwardly away from the tires 30 to their disengaged positions.

The invention is also embodied in means for manually releasing the braking means 42 to utilize the chair 2 as a walker. An inwardly projecting strut or bracket 54 is rigidly secured to one of the rear frame members 12, and a brake release lever 58 is pinned to the inner end of this strut 54. The release lever 58 is connected at its inner end to the inner control ends 41 of the brake arms 42 by means of a flexible, non-stretchable Y-cable 60'. The outer end of the release lever 58 is connected to a liexible release cable 62 which extends upwardly along the adjacent upstanding rear member 12 through a sheath 64. At its upper end the sheath 64 attaches to a bifurcated bracket 66 mounted on the horizontal end portion of the upstanding rear member 12 adjacent to the hand grip 14, Journaled intermediate the furcations of the bracket 66 is a hand lever 68 which is connected to the upper end of the cable 62 so that when the lever is moved toward the hand grip 14, the cable 62 will be drawn through the sheath 64. In this embodiment an auxiliary tension spring 70 may be provided between the inner end of the brake release lever 58 and the rear frame member 12 to supplement the force of springs 45 acting through the control linkage in maintaining the cable 62 taut.

The chair 2 with brake assembly 40 is used similarly to any conventional wheelchair. When the invalid is seated upon the seat panel 36, the webs 46 and 48 and the actuating members 50 are depressed from the normal elevated position. The actuating members 50 acting through the cables `52 rotate the brake arms 42 to the disengaged positions thereof against the bias of the springs 45 and the rear wheels 28, as well as the wheelchair 2 itself, are free to move (assuming the conventional hand brakes are released). However, when the invalid rises from the seat panel 36, the tension springs `45 act on the control ends 41 and rotate the brake arms 42 causing the braking margins 41 to engage the tires 30, thus locking the wheels 28 against rotation and immobilizing the chair 2. Accordingly, even though the invalid may neglect to set the conventional brakes, the chair 2 is automatically immobilized by the brake assembly 40 when the invalid is attempting to rise from or seat himself in the chair 2.

When it is desired to move the chair 2 without the invalid in it, the hand lever 68 is merely squeezed toward its adjacent hand grip 14 to draw the release cable 62 upwardly through the sheath 64 and rotate the release lever 58 on the strut 54. The inner end of the release lever 58 shifts downwardly and, acting through the Y- cable 60, moves the brake arms 42 into their disengaged positions against the bias of the springs 45. Thus, a semi-invalid or recuperating patient can safely employ the chair 2 as a walker, for if for some reason he loses his balance, he need only release his grip on the hand lever v68 to bring the chair 2 to an immobilized condition of suflicient rigidity to enable him to lean against it and regain his balance.

The brake assembly 40` in no way interferes with the structural members of the main frame 4 and, consequently, the, chair 2 is collapsible in the conventional manner. It will be readily apparent tha't the braking means 40 are released automatically in response to a relatively short, vertical displacement of the seat control levers 50.

Referring now to FIGS. 4-6` in which a wheelchair 102 is provided with a modified brake assembly 140` embodying the invention, the wheelchair 102 is substantially the same as the chair 2 just described and the same reference numerals are applied to similar parts. Similarly, the brake arms 42 are pivotally mounted on the side frames 6 for movement between a tire engaging or braking position and a disengaged or released position, and the parts and relationship of the brake arms 42l and the wheelchair frame 4 may be the same as previously described. However, in this embodiment the seat control means having a short vertical displacement for operating the braking arms 42 is incorporated in structural changes in the wheelchair 102 as will now be described.

The longitudinal bars 34 of the seat unit 5 are interconnected with the side frames 6 of the wheelchair 102 by the front and rear cross 4members 8 and 10, the front members `8 being attached to the lower member 16 as previously described. However, the lower ends of the rear cross members 10` are adapted for limited predetermined vertical movement relative to the vertical rear members 12 in the open position of the wheelchair 10'2.

A short vertical slot 104 is provided at the lower end of each rear frame member 12, and relatively strong springs 106 are housed within the tubular members 12. Control or actuating rods 108 are connected to the opposed inwardly eXtendng control portions 41 of the brake arms 42 and are formed with right-angle extension pins 110 positioned through the slots 104 and pivotally connecting the control rods 108 with the lower ends 112 of the cross members 10i. The springs 106 are compressed between the lower members -16 and the extension pins 110 to exert a predetermined force normally biasing the control rods 108 upwardly to rotate the braking margins 41 into engagement with the tires 30.

It will now be apparent that when someone sits on the seat panel 36, a force will be exerted downwardly through the rear cross members 10 acting in opposition to the springs 106 so that the seat unit 5 will ride downwardly slightly at the rear portion and carry the control rods 108 to actuate the brake arms 42 to their disengaged positions.

A modified manual release means is also disclosed in FIGS. 4-6. A hand lever 114 is provided on each handle 14 and is connected to a cable 116 which extends around a pulley 118 mounted on the rear frame member 12 above the brake arm 42. The other ends of these cables 116 are connected to their respective brake arms 42 at a point vertically above the brake margins y41 thereof. When it is desired to move the wheelchair 102 without a patient or to utilize it as a walker, the hand levers 114 are squeezed against the handles 14 to pull the cables 116 and' the outer ends of the brake arms 42 upwardly to a brake release condition.

Referring now to FIGS. 7 9, a wheelchair 202 is provided with another modified brake assembly 240. In this embodiment the seat unit is also adapted for limited vertical movement through the rear cross members 10. A slot 204 is formed in the rear members 12 adjacent to the lower members 16 and the lower ends 212 of the cross members 10 are pivoted on pins 210 extending through the slots 204. If desired, spring means (not shown) may be provided between the pins 210 and the lower frame members 16 to cushion the vertical seat displacement.

The brake assembly 240 includes a pair of brake arms 220 which are mounted on pins 222 projecting outwardly from plugs 224 litted into the rear end of the horizontal members 22 and secured thereto by means of cross pins 226. The plugs 224 are provided with annular recesses 228 containing spiral springs 230 which wrap around the pins 222 and bias the brake arms 220 toward engagement with the tires 30 of the wheelchair 202. The inner ends 232 of the brake arms 220 are disposed above the ends of the seat bars 34 and are connected thereto by exible non-stretchable cables 234. When the wheelchair is unoccupied the rear ends of the seat bars 34 are in the upper vertical position and the brake arms 220 are biased into brake engagement by the springs 230.

When an individual sits on the seat panel 36 attached to the seat bars 34, the rear end of the seat bars will move downwardly through vertical displacement of the lower ends 212 of the cross members 10 relative to the frame members 12. Since the slots 204 are vertical, the rear cross members 10 are prevented from spreading laterally during this downward movement. As the seat bars 34 are depressed downwardly, the cables 234 are drawn downwardly and pivot the brake arms 220 against the bias of the springs 230 causing the brake arms 220 to retract from engagement with the tires 30 of the wheelchair 202.

Any suitable release mechanism can be utilized to manually release the brake arms 220 from the tires 30. Another modified release is shown in FIG. 7 in which a release cable 236 is channelled through the rear frame member 12 between a hand lever (as previously described) and outwardly through an elongated slot 237 around a pulley 238 positioned below the seat unit 5. The cable is connected to the seat bar 34 through a disconnect link 239. Accordingly, when the hand lever is grasped, the cable 236 will be drawn upwardly in the frame member 12 and, acting around the pulley 238, will exert a downward force on the seat unit 5.

In the embodiment shown in FIGS. 7-9 the rear panel 38 is slotted, as at 241, to accommodate the connection of the cables 234 to the seat bars 34 and provide for a cable loop when the wheelchair 202 is folded and the seat bars 34 are elevated to their collapsed position ad'- jacent to the upper frame members 22.

It will be apparent that other modifications of the brake assembly according to this invention may be provided. The brake arms may be angularly mounted on the lower frame members 16 for engagement with the tires 30 and connected to seat and hand release control means through suitable cable linkage extending around pulleys on the rear frame members 12. However, in this position the brakes would be hidden from the invalid utilizing the chair as a walker and visibility of these brakes may be desirable.

A brake assembly can also be utilized with noncollapsible wheelchairs. These chairs (not shown) normally have seat panels which are more or less rigid, and by hinging these seat panels near their forward ends and attaching the actuating or control means to the bottom of the seat panel the same result will be achieved, since when the invalid sits upon the seat it will swing about the hinge and force the outer ends of the actuating means downwardly against the bias of the brake springs to shift the brake arms to their disengaged positions.

It will also be apparent that the present wheelchair brake invention can be provided on existing conventional chairs by supplying the parts in kit form.

The invention is intended' to cover all changes and modiications that will be readily apparent to those skilled in the art.

What is claimed is:

1. A brake assembly kit for modifying a conventional 4wheelchair for use as a walker, said wheelchair comprising a main frame having opposed tubular side frames with vertical rear members, drive wheels rotatably mounted on said rear members, a back panel supported between said rear members, rearwardly extending rigid hand supports formed on the upper ends of said rear members, and a seat unit supported on said main frame between said side frames; said kit when installed on the wheelchair comprising at least one brake arm with a braking margin, bracket means pivotally mounting the brake arm on the main frame adjacent to a drive wheel with said braking margin extending transversely across said wheel relative to the direction of rotation thereof, spring means mounted between the main frame and said brake arm for urging the braking margin into braking engagement with the wheel, actuating means mounted between the seat unit and the brake arm to act in opposition to the spring means under the weight of an individual seated on the seat unit, and manual means mounted adjacent to one of said hand supports for use by an individual in a walking position to selectively disengage said braking margin from said drive wheel to permit wheelchair movement and selectively reengage said braking margin against said wheel to prevent wheelchair movement and support the individual.

2. A wheelchair comprising a main frame having rigid side frames with vertical rear members, main drive wheels rotatably mounted on said rear members, a back support extending between said rear members, a seat unit supported between said side frames and at least a portion of said seat unit being adapted for limited vertical displacement between an unoccupied upper position and an occupied lower position, and a brake assembly having brake arms pivotally connected to said main frame adjacent to said rear members, said brake arms having braking margins extending transversely to the direction of rotation of said wheels for braking engagement therewith, -control means connected with said brake arms and responsive to seat unit displacement to said lower position for disengaging said braking means from said wheels to permit wheel rotation, spring means acting on said seat unit to move it to said upper position and acting on said braking means to -urge it into braking engagement,

said brake arms and control means and spring means being positioned at the rear of said seat unit and side frame out of normal reach of an occupant of said wheelchair and operating automatically to engage said brake arms and prevent wheel rotation during seat unit displacement to said upper position without interference by the occupant.

3. The wheelchair according to claim 2 including rearwardly extending hand supports for a person in a Walking position behind the wheelchair, and manual means for selectively actuating said brake arms to a disengaged position for permitting wheelchair movement and selectively re-engaging said braking margins against said wheels to prevent wheelchair movement and support the person.

4. The wheelchair according to claim 3 in which said manual means comprises dual hand levers mounted on said hand supports, and cable means directly connecting said hand levers with the respective side brake arm above the braking margin thereof.

5. The wheelchair according to claim 3 in which said brake arms have inner control ends, and said manual means comprises hand lever means mounted adjacent to said hand supports, and means for connecting said hand lever means with said inner control ends of said brake arms.

6. The wheelchair according to claim 5 in which a single hand lever is mounted on one of the rearwardly extending hand supports, and said last mentioned means comprises a cable and lever linkage connecting the hand lever to the seat responsive control means and adapted to simultaneously disengage both of said brake arms.

7. A wheelchair adapted for use as a walker and having a main frame mounted on wheels, a seat unit carried by said main frame, and said main frame having rearwardly extending rigid hand supports for a person in a walking position behind the wheelchair, and a brake assembly for said wheelchair comprising braking means mounted on said main frame, spring means urging the braking means into braking engagement with at least one of said wheels, actuating means associated with said seat unit and coupled to said braking means to act in opposition to said spring means under the weight of a person seated on said seat unit for disengaging said braking means from said Wheel, and manual means adjacent to said hand supports for selectively disengaging said braking means from said wheel.

8. The wheelchair according to claim 7 in which said main frame includes frame member means positioned rearwardly of said seat unit and adjacent to the periphery of the wheel, and said braking means comprises a brake arm pivotally connected intermediate its ends to the frame member means for movement about an axis extending generally perpendicular to the rotational axis of the Wheel, said brake arm having an outer braking margin extending transversely of the peripheral surface of the wheel and having an inner control end, and said spring means is connected between said main frame and said inner control end to bias the outer braking margin substantially radially inwardly against said wheel surface.

9. The wheelchair according to claim 8 wherein the brake arms are mounted on plug means inset into said frame member means of said main frame, and said spring means are spiral springs connected at one end to a brake arm and connected at the other end to said plug means.

10. The wheelchair according to claim 8 wherein the seat unit has a flexible seat panel, and said actuating means comprises a rigid control lever extending rearwardly from beneath the seat panel, and connecting means between the rearward end of the rigid control lever and the inner control end of said braking means, said connecting means elevating said control lever and flexible seat panel above the normal occupied position thereof when said braking margin is in wheel engagement.

11. The wheelchair according to claim 7 wherein at least a portion of the seat unit is carried on the main frame by a vertically shiftable supporting structure and said spring means urges the supporting structure upwardly, and said actuating means comprises connecting means interconnecting the braking means and supporting structure.

12. The wheelchair according to claim 11 wherein said seat unit comprises a exible seat panel secured at its side margins to substantially horizontal seat bars, and said supporting structure comprises a pair of pivotally connected diagonally extending members having upper ends secured to said seat bars and lower ends pivotally and vertically slidably connected to said main frame.

13. The wheelchair according to claim 12 in which a vertical slot is formed on each side of the main frame and a horizontal extension element extends through the slot for vertical sliding movement therein, said elements forming the pivotal connection of the diagonal members lower ends to said main frame, said actuating means comprising a rigid control rod connected between at least one of said extension elements and said braking means, and said spring means bearing against the extension elements and urging them toward the upper ends of said vertical slots to engage said braking means with said wheel.

References Cited UNITED STATES PATENTS 2,117,617 5/1938 Littlefield 188-109 2,437,778 3/1948 Ames 188--29 X 3,237,940 3/1966 Johnson 188-29 X 3,280,933 10/1966 Jones 18S-109 X 3,302,757 2/1967 Eagleson et al. 18S-167 GEORGE E. A. HALVOSA, Primary Examiner U.S. Cl, X.R. 188-2, 29, 167; 280-42 

